When to sow lupines? A detailed guide to lupine growing methods

“Every night I think of mother's words, the glistening tears of lupines” - mention this lyric, and surely many people cannot help but recall the widely sung song "Lupine." The song is lovely, but do you really know the real lupine? The lupine is a vast family, with as many as several hundred species. The mini lupine barely reaches past your ankles, while the tall tree lupine is a giant several metres high. Among them, the most popular is none other than the “high-appeal branch” - their spire-shaped flower spikes are enormous, reaching several dozen centimetres tall, with brilliant flower colours.When to sow lupines? How to grow them?

1. When to sow lupines?

Lupine seeds can be sown in spring or autumn. The best time for spring sowing is February to April, and the best time for autumn sowing is September to October. Lupine is a plant in the order Rosales, family Fabaceae, genus Lupinus. The flowering period is March to May, and the fruiting period is April to July. It can be used for garden viewing. Tea farmers in the mountains of Taiwan, China, plant “lupines” near the tea plants to serve as green manure.

2. How to grow lupines?

1. Temperature

Lupines like a cool climate and cannot tolerate heat. In winter they can briefly tolerate low temperatures around zero degrees. Generally, growers are advised to move them indoors once the temperature drops below ten degrees. Lupines likewise cannot tolerate high temperatures; when the temperature rises above 30 degrees they go dormant. Many growers choose autumn sowing, following a growing cycle of flowering in spring and setting seed in early summer, to avoid the high-temperature period of summer. Those who sow in spring should pay attention to summer care, because lupines are highly prone to disease when overwintering through summer.

2. Light

Lupines love light. With sufficient light they grow well, with sturdy branches, thick and long flower spikes, and abundant, vivid blooms. They tolerate slight shade; under insufficient light they tend to grow leggy, with weak branches, dull leaf colour, small flower spikes with few blooms, and a low seed-setting rate, greatly reducing their ornamental value.

3. Soil

Lupines have certain soil requirements. They are suited to growing in slightly acidic soil. Growers in the north should note one thing: avoid using ferrous sulfate and aluminium sulfate long-term to adjust soil acidity and alkalinity, because the cations in these two regulators accumulate in the soil and become toxic to the plants. It is recommended to use pond mud mixed with leaf mould as the potting soil for growing lupines.

4. Fertilising

Lupines have low requirements for nitrogen fertiliser, because the rhizobia living in their roots can fix nitrogen, providing nitrogen for plant growth. However, they have relatively high requirements for phosphorus and potassium fertiliser. Sufficient phosphorus and potassium fertiliser can promote flower bud differentiation, increase flower spike length while making flower colours vivid, and raise the seed-setting rate after flowering.

5. Propagation

Lupine propagation is mainly by seed. Generally, growers choose autumn sowing; during winter care they can enjoy the foliage, then in spring enjoy the flowers, and after setting seed in summer the plant dies - this conveniently avoids the situation where the high-temperature summer period, when disease is frequent, is difficult to manage. Some growers also take cuttings in spring from branches sprouting from the roots, cutting these branches into 10 cm segments, soaking them in rooting powder, and then inserting them into clean, moist sand. Generally, in about a month and a half they develop a complete root system and can be transplanted.

6. Pests and diseases

Common lupine diseases include root rot, rust and powdery mildew. These diseases are all caused by fungi. The causes of onset are related to high temperature and high humidity and to excessive planting density leading to poor air circulation. Effectively avoiding onset is possible by improving environmental air circulation. Some flower nurseries spray regularly to prevent onset, but over time the pathogens develop resistance, making it harder for growers to deal with disease when they find it after buying a mature plant. Therefore, when selecting plants, observe carefully; it is best not to buy any that have white chemical residue on their leaves.